1. Field of the Invention
The present invention relates to a rotating electric machine and a manufacturing method thereof.
2. Description of the Related Art
In general, steel plate material of magnetic steel plates used for a rotor of a rotating electric machine is roll formed. With the process of manufacture of rolling, deviations are unavoidable in widthwise thickness of the steel plate material. In the event that such steel plate material is punched so as to manufacture rotor plates used for laminated bodies such as rotor cores, deviations in thickness having a certain directionality according to rolling direction remain on each of the rotor plates.
When steel plate material is punched keeping the rolling direction and the produced rotor plates are laminated so as to manufacture a laminated body such as rotor cores, tiny amount of deviation in thickness included in each of the rotor plate materials is accumulated in the laminated body and comes out as a large amount of deviation in thickness. A great mass imbalance occurs at a rotor in which the laminated body is assembled as it is manufactured. In order to resolve the mass imbalance, a balancing process is provided after the assembly, and the final mass balance is achieved by boring therein an adjustment hole or the like.
There is a method known in the related art in which rotor cores are manufactured by laminating rotor plates with rotating the direction of each plate, which we call as “rotary lamination”, so as to avoid such accumulation of deviations in thickness in the laminated body (refer to Japanese Laid Open Patent Publication No. 2009-33908).